Steam-boiler



(No Model.)

D. MOB. GRAHAM.

'STEAM BOILER No. 286,695. Patented Oct. 16, 1883.

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UNITED STATES PATENT O FICE.

DANIEL MOB. GRAHAM, OF CHICAGO, ILLINOIS;

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 286,695, dated October18, 1888. Application filed February 23, 18ers. (No model.)

To all w/wm it may concern:

, Be it known that I, DANIEL. MCBRIDE GRAHAM, of Chicago, 'in the countyof Cook, of the State of Illinois, have invented a new and usefulImprovement in Steam-Boilers and I do hereby declare the same to bedescribed in the following specification and represented in theaccompanying drawings, of which Figure 1 is a longitudinal and mediansection, and Fig. 2 atransversesection, of a steamboiler provided withmy invention, the nature of which is defined in the claim hereinafterpresented. The plane of section of Fig. 2 is through the branchedconduit of the air-distributing ring, as explained.

The boiler is a multitubular one, such as is in common use in locomotivesteam-engines, its fire-place being at A, grate at B, tube-stack at O,smoke-chamber at D, chimney at E, and outer shell at F. The bars a ofthe grate are tubular, each of them, nearits rear end, opening into aflaring mouth-piece, 1), extending along underneath the set and opentoward the front end of the engine. Each tubular grate-bar, at or nearits front end, opens into a receiver or box, G, extending across the seti at the back of the fire-chamber, such tube being closed at its ends.

From this tube a branched conduit, H, leads, and opens communicationbetween the receiver G and a ring, I, arranged directly in rear of andwith respect to the receiving-mouths of the tubes of the stack, inmanner as represented, this ring having numerous holes made in it at itsinner periphery, the obj eet of the said tube being to receive anddischarge airinto the combustible smoke and gases just previous to theirpassage into the several tubes, the'same being to promote and facilitatethe combustion of such smoke and gases, and thereby not only utilizethem to advantage in heating the tubes,but preventing deposits from thembeing made in the tubes or smoke-box. The flaring mouthpiece b extendsunderneath all the grate-bars, and serves not only to conduct air intothem,but as a support for them, they at their rear ends being supportedby the receiver G, which extends across and is fastened to them. Thegratebars are open at their front ends, and should be there providedwith one or more covers or draft created in the stack, and will passintoand through the hollow grate-bars, thence into the receiver, thenceinto and through the branch conduit, thence into the ring and out of itsperforations, the air passing through the grate-bars preserves them in ameasure from destruction by the heat of the fire on them, and becomesheated by them, and thereby facilitates combustion of the gases andsmoke.

I do not claim, in a tubulargrate, each of its bars provided with amouthpiece separate from that of each of the other bars. I have a singlemouth-piece to all the grate-bars, it extending across and under them attheir outer ends, and serving to support them and to better supply themwith air. I would remark that by having the branched conduit H to leadfrom the receiver G to the ring I communication with the ring fromeither half of the gratebars may be maintained, while the others may beopened at their rear ends for being cleaned. I do not herein claim thearrangement,in a firebox, of an arched or perforated firc-brick annularcasting to receive air and discharge it into the throat of the saidfire-box, and to open to the atmosphere by a short conduit leadingdownward from it through the shell of the boiler of such fire-box.

I claim In the multitubular boiler, the combination of the tubular andperforated ring I, arranged with the tube-stack, as described, thebranched conduit H, the receiver G, the series of tubular grate-bars a,and the mouth-piece I), extending across and under such bars and servingto support them and supply them with air, as explained.

DANIEL MQBRIDE GRAHAM.

\Vitnesses:

R. H. EDDY, E. B. PRATT.

